It is GBNeed pics of drums as well. Serials alone don't tell the whole story.
GBVälkommen!
4417 should be a 14x14 floor tom. Serial indicates late 80s, perhaps 1988? KSWW could the finish, but I don't know what it means. WW is walnut, DKWW dark walnut (nonstandard finish in 87 price list). Are the upper letters GB or CB?
Just saw the pic: those are Broadcasters. US custom drums, but with gunmetal hardware.